Top lock mechanism for presses



1970 R. M. GLASGOW ETAL 3,492,940

TOP LOCK MECHANISM FOR PRESSES Filed June 15, 1968 5 Sheets-Sheet 1 IO 0 0000.000.- I 8 oooo'ooo INVENTORS ROBERT MGLA BY ROBERT AHELRIGEL ATTORNEYS.

Feb. 3, 1970 R. M. GLASGOW ET AL- 3,492,940

TOP LOCK MECHANISM FOR PREssEs Filed June 13, 1968 5 Sheets-Sheet 2v FIG.2

INVENTORS ROBE RT M GLASGOW BYROBERT A. HELRIGEZL WWW ATTORNEYS.

Feb.3, 1910 M. GLASGOW ET AL "3,492,940-

TOP LOCK MECHANISM FOR PRESSES 5 SheetsSheet 3 Filed Jun 13, 1968 FIG. 3

ROBERT w'l gf gow BYROBERT AIHELRIGEL ATTORNEYS.

Feb. 3, 1970 R. M. GLASGOW ET AL TOP LOCK mmcmmzsm FOR PREsss 5 Sheets-Shet 5 Filed June 13, 1968 QUE ATTORNEYS.

United States Patent 3,492,940 TOP LOCK MECHANISM FOR PRESSES Robert Morris Glasgow and Robert Arthur Helrigel, Hastings, Mich, assignors to E. W. Bliss Company, Canton, Ohio, a corporation of Delaware Filed June 13, 1968, Ser. No. 736,617 Int. Cl. B30b /00; 821i 13/00 U.S. Cl. 100257 7 Claims ABSTRACT OF THE DISCLOSURE A top lock for a press comprising a jack screw mounted on a locking plate. A sprocket received over the jack screw is driven by a flexible chain and ratchet mechanism to adjust the jack screw.

This invention relates to the art of presses and, more particularly, to a top lock assembly for a knuckle joint press.

Knuckle joint presses are designed for work which requires slow, powerful pressure close to the bottom stroke. Coining, embossing, extruding, heading, sizing and swaging are examples of operations in which knuckle joint presses are employed.

A typical construction of a knuckle joint press is illustrated in US. Patent No. 2,320,103. As there described, the slide of the press is reciprocated by a pair of toggle links or knuckles. One toggle or knuckle is pivotably connected to the slide which reciprocates in the frame while the other tog le is pivotally connected to a block which is in engagement with the press frame. The two toggles, as in a conventional toggle mechanism, are pivotably connected at their adjacent ends with a connecting rod driven by the crankshaft causing the toggles either to be extended, which causes the slide to move through its stroke to a bottom position, or collapsed, wherein the slide is retracted to its top of the stroke position.

It is conventional in knuckle joint presses to employ an adjusting wedge which is interposed between the crown and the block to which one of the toggle or knuckle joints is secured. This wedge provides an adjustment of the slide mechanism in a manner well known in the art and described in the aforementioned patent.

To accommodate the adjustment of the slide by the wedge, the block to which the one knuckle joint is connected is supported by a spring suspension which allows the block to move with respect to the frame. This spring suspension comprises rods connected at one end to the block and extending through the crown. Springs sur round the rods and normally biasing the rods in an upward direction thereby maintaining the block in engagement with the adjusting wedge which, in turn, engages the crown. This arrangement has proven generally satisfactory; however, during operation of the press and particularly at relatively high speeds, there is a tendency for the slide assembly including the block to compress the springs and pull the block away from the press crown. This action is accompanied by a substantial banging of the block against the crown and resultant vibration of the entire press frame.

To overcome this problem, the prior art has evolved a top lock assembly the function of which is to lock the block to the wedge and crown thereby preventing any movement of the block away from the crown of the press. This typical prior art construction of a top lock assembly is fully described in the aforementioned prior patent.

As described in that patent, the top lock assembly comprises a locking plate through which a threaded lock- 3,492,940 Patented Feb. 3, 1970 ing bolt or jack screw is received with the bolt being adapted to engage the top of the crown. The upper end of the spring rods extend through the lock plate and by threading the lock bolt, the lock plate is moved away from the crown and thereby carries with it both the spring rods and the block to which the spring rods are connected. As is well understood in the art, it is necessary to adjust the top lock each time a wedge adjustment of the slide is made. Heretofore and as described in the aforementioned prior patent, the adjustment of the lock bolt was made by a series of bevel gears and shafts which were manually operated with a chain and pulley arrangement. It was often difficult to adjust the block bolt or jack screw when the bevel gears were under load. Moreover, the use of a chain and pulley limited the amount of torque that could be applied to make the adjustment of the jack screw.

It is the principal object of this invention to provide an improved adjusting mechanism for the top lock assembly of a press.

It is a more specific object of this invention to provide an adjusting mechanism for a top lock assembly in which higher levels of torque may be manually applied to adjust the top lock.

It is a further object of this invention to provide a top lock assembly in which the adjusting torque is applied around the center of the jack screw.

More specifically, this invention contemplates a sprocket which applies the adjusting torque around the center of the jack screw thereby eliminating the offcenter loading experienced with the previous bevel gear arrangement. A ratchet drive is employed for the sprocket with the ratchet permitting the operator to apply greater torque in adjusting the jack screw. A flexible drive chain interconnects the ratchet drive with the sprocket thereby isolating the ratchet mechanism from the loads imposed on the jack screw and the sprocket.

Other features and advantages of the invention will become more apparent upon a complete reading of the following description which, together with the attached drawings, describes but one preferred embodiment of the inventlon.

Referring now to the drawings wherein like reference numerals indicate like parts in the various views:

FIGURE 1 is a front elevation view of a press incorporating the features of the invention;

FIGURE 2 is a fragmentary front elevation view showing a portion of the crown and the top lock assembly;

FIGURE 3 is a plan view of the crown and the top lock assembly;

FIGURE 4 is a fragmentary sectional view of the top lock assembly;

FIGURE 5 is a side elevation view of the view of FIG- URE 4;

FIGURE 6 is a plan view of the portion shown in FIGURE 5;

FIGURE 7 illustrates in plan view the ratchet drive for the top lock assembly;

FIGURE 8 is a side elevation view of the ratchet mechanism of FIGURE 7.

Referring now to FIGURE 1, there is illustrated a knuckle joint press in which the invention is incorporated. As is conventional in the construction of such presses, there is provided a bed 10 which supports vertical uprights 12. A crown 14 is supported on the upper ends of the uprights 12. Heavy tie rods, not shown, extend through the crown and uprights at the four corners of the machine with the tie rod nuts 16 engaging the rods and serving to hold the parts of the press frame in an assembled relationship.

A slide 18 is supported by ways 20 for reciprocating movement in the press frame. The reciprocation of the slide 18 is controlled by a motor driven crankshaft and a pair of toggles or knuckle joints in a manner which is conventional in the press art. The upper toggle link or knuckle is pivotably connected to a block 22 which is slidably supported by appropriate gibs, not shown, in the frame of the press. Spring rods 24 are connected at one end to the block 22 with the spring rods extending through appropriate apertures in the crown 14 and upwardly of the crown. Springs 26 encircle a portion of each spring rod 24 with the springs being bottomed in an upwardly opening aperture 28 in the crown. The other end of the spring is compressed by a lock plate assembly indicated generally by the reference numeral 30. It will be apparent that with this arrangement, the springs 26 tend to bias the lock plate, and thus the spring rods which are secured to the lock plate by nuts 32, in an upward direction. This same biasing movement carries with it the block 22 and the slide to which the block is connected through the knuckle joints.

To adjust the position of the block and the slide in the press, there is provided a wedge adjusting mechanism, indicated generally by the reference numeral 40. This wedge adjusting mechanism comprises a wedge member 42 which has an inclined surface 44 on the lower surface thereof and a planar surface 46 on the upper surface. The planar surface 46 is adapted to engage a correspond ing planar surface 48 formed on the lower surface of the crown 14 with the inclined surface 44 being adapted to engage a corresponding inclined surface on the block 22. A wedge nut 50 is carried by the wedge member 42 and is adapted to cooperate with a wedge adjusting screw 52 to move the wedge member 42 from right to left as viewed in FIGURE 2. The rotation of the wedge adjusting screw 52 may be accomplished either manually or by a power adjustment, both of which are well known in the art. As illustrated, an adjusting gear 54 is connected to the adjusting screw 52 and the gear 54 may be driven by appropriate power means to effect the adjustment of the wedge.

As the wedge is adjusted from right to left as viewed in FIGURE 2, the block 22 will be displaced in a downward direction. The springs 26 and spring rods 24 serve both to maintain the block in engagement with the wedge member 42 and the wedge in engagement with the crown 14; however, as pointed out above, during high speed operation or under certain other conditions, there may occur a situation in which the block separates from the wedge member and/or the wedge and block separate from the crown resulting in a recurrent banging of the block and wedge against the crown.

To eliminate this situation, the top block assemblies heretofore described have been employed by the prior art. In accordance with this invention, a top lock assembly is also incorporated herein. The lock plate 30 supports the top lock mechanism, indicated generally by the reference numeral 60. This top lock mechanism is best viewed in FIGURES 4, and 6. As shown in those figures, the top lock assembly comprises a jack screw housing 62 which is supported by threaded fasteners in an aperture 64 in the lock plate 30. A jack screw 66 is threadedly received in a threaded bore 68 in the housing 62 with one end 70 of the jack screw extending beneath the lock plate and being adapted to engage the top of the crown in the manner shown in FIGURE 2. It will be appreciated that rotation of the jack screw 66 will, through the threaded engagement in the bore 68, cause extension or retraction of the jack screw relative to the housing 62.

To rotate the jack screw 66, there is provided a sprocket 72 received over the jack screw and which rests on the upper end of the housing 62. The sprocket is connected for rotation with the jack screw by a key received in a keyway 74 formed in the jack screw. The key has a sliding fit with the keyway 74 formed in the jack screw. The key has a slid ng fit with the keyway 74 so that although the sprocket is restrained from rotation relative to the jack screw, the jack screw may move longitudinally relative to the sprocket 72. The sprocket is maintained in supported engagement with the housing 62 by springs 76, one end of which abut the sprocket 72 with the other end of the spring being received in a cap 78. The cap is secured by a set screw and cap screws 82 to the upper end of the jack screw 66.

The described relationship of the sprocket 72 and the jack screw 66 thus permits the jack screw to be rotated by the sprocket 72. Upon rotation of the sprocket and the jack screw, the threaded engagement of the jack screw with the bore 68 causes the jack screw to travel longitudinally, which movement is accommodated by the sliding fit of the key in the keyway 74.

Rotation of the sprocket 72 is achieved by a drive chain 84 which interconnects the sprocket 72 with a sprocket 86 rotatably supported at one edge of the lock plate 30. The sprocket 86 is connected to a sprocket shaft 88 which, in turn, is connected to a universal joint 90. An elongated adjusting shaft 92 extends from the universal joint 90 down the side of the press to a position adjacent to the bed of the press wherein the shaft is journaled in an appropriate bracket on the press frame. It will be an appropriate bracket on the press frame. It will be appreciated that rotation of the adjusting shaft 92 causes rotation of the sprocket 86, which rotation is then transmitted by the drive chain 84 to the sprocket 72 and thence to the jack screw 66.

It is contemplated that the adjusting shaft 92 will be driven by a manually operated ratchet mechanism. This ratchet mechanism is illustrated in FIGURES 7 and 8 and is designated generally by the reference numeral 100. The ratchet mechanism comprises a ratchet lever 102 and a cover plate 106 adapted to be received over the end or the shaft 92. A ratchet wheel 104 is supported between the lever 102 and plate 106 with the wheel being adapted to be connected to the end of shaft 92. A pawl 108 is pivotably supported on shaft 110 between the cover plate 106 and the lever 102 with the pawl being adapted to cooperate with the teeth 104a on the ratchet 104. A fulcrum pin 112 extends between the cover plate 106 and the lever 102 and pivotably supports a plunger housing 114. The plunger housing includes a plunger 116 and a spring 118 biasing the end of the plunger 116 into engagement with the pawl 108. A trip pin 120 extends outwardly of the cover plate 106 and is operative to rotate the housing 114 about the fulcrum 112 and thereby reverse the direction of operation of the ratchet. The ratchet lever 102 includes a handle portion 122 in which there is formed an aperture 124. A rod or other extension may be received in the aperture 124 and thereby provides an elongated handle for actuating the ratchet mechanism and driving the top lock assembly.

The ratchet mechanism described operates in the following manner. Assuming the parts to be in the position illustrated in FIGURE 7, it is apparent that one tooth 108a of the pawl is in engagement with one tooth 104a of the ratchet wheel 104 and will be operative to drive the ratchet wheel and hence the shaft 92 in a counterclockwise direction when the lever 102 is rotated in that direction. The ratcheting effect is achieved by rotating the lever in the counterclockwise direction thereby driving the ratchet wheel through a predetermined are. Thereafter, the direction of rotation of the ratchet lever 102 is reversed and as the lever moves clockwise, the ratchet wheel 104 remains stationary due to the disengagement of tooth 108a and tooth 104a. The clockwise movement of the lever causes the teeth 104a on wheel 104 to engage an arcuate surface 1080 on the pawl 108 and thereby pivot the pawl to a position wherein both teeth on the pawl are radially spaced from the ratchet wheel. This pivoting or ratcheting movement of the pawl is accommodated by displacing the plunger 116 against the bias of the spring 118; however, when the clockwise rotation of the lever is discontinued, the ratcheting of the tooth 108a over the teeth 10411 of the ratchet wheel will cease and the spring 118 will cause the plunger to pivot the pawl to its driving position as illustrated in FIGURE 7. Thereafter the lever is moved again in the counterclockwise direction and further rotation is imparted to the adjusting shaft 92.

In the event that it is desired to rotate the shaft 92 in a clockwise direction as viewed in FIGURE 7, the trip pin 120 is actuated to pivot the housing 114 about the fulcrum pin 112. As the housing is pivoted, the plunger 116 is compressed against the spring 118 until it has passed beyond the centerline of the shaft 110; thereafter, the plunger, under the bias of the spring 118, will exert a biasing force on the pawl in a direction which tends to pivot the pawl counterclockwise about the shaft 110 and thereby bring the tooth 10812 of the pawl into engagement with the teeth of the ratchet wheel. Correspondingly, the tooth 108a will be separated from engagement with the ratchet wheel. Thereafter, movement of the ratchet wheel in a clockwise direction as viewed in FIGURE 7 will cause the pawl to drive the ratchet wheel in the clockwise direction.

It is apparent that as the ratchet wheel rotates, so also the adjustment shaft is rotated which, as stated above, transmits rotation to the sprocket 72. It is to be noted in this regard that the rotation of the sprocket 72 is around the center of the jack screw 66 and there is no off-center loading to which either the sprocket or the drive mechanism may be subjected. Accordingly, any possibility of binding the key interconnecting the sprocket with the jack screw is eliminated and thus a free sliding motion vertically of the jack screw relative to the sprocket is obtained. Moreover, the flexible drive chain 84 isolates the ratchet drive system from any binding action that may occur in the top lock assembly.

An added advantage of this arrangement is that the ratchet drive permits the operator to apply more torque than was heretofore possible with the conventional chain drive. Thus, by simply inserting a rod of greater length in the ratchet handle 22 the operator can increase the torque which he applies in adjusting the top lock assembly. Moreover, once the top lock has been adjusted, the ratchet handle can be removed thereby eliminating an element which might otherwise be in the way of the press operator. The end of shaft 92 is positioned on the frame adjacent the bed of the press so it is convenient to the operator when adjustments are to be made.

Having thus described our invention, we claim:

1. In a press having a frame including a crown, a slide reciprocably mounted in said frame, a block slidably supported in said frame, knuckle joint means interconnecting said block through said slide, passages through said crown with rods extending through said passages and secured to said block, a locking plate above said crown and connected to said rods with spring means normally biasing said locking plate and rods in an upward direction, and a top lock assembly carried by said locking plate adapted to lock said plate against downward movement relative to said frame, the improvement comprising:

said top lock assembly including a jack screw threadedly supported on said locking plate and adapted to engage the top of said crown;

drive means received over one end of said jack screw;

means interconnecting said drive means with said jack screw for rotation therewith while permitting longitudinal movement of said jack screw relative to said drive means; and

ratchet means for incrementally rotating said drive means.

2. The improvement of claim 1 wherein said threaded support for said jack screw comprises a jack screw housing with said jack screw being threadedly received therein,

said drive means being rotatably supported on said housing.

3. The improvement of claim 2 wherein said drive means comprises a sprocket,

cap means secured to said jack screw, and

means biasing said sprocket in a direction away from said cap means and into engagement with said housmg.

4. The improvement of claim 1 wherein said drive means comprises a sprocket, and

flexible drive transmitting means interconnecting said ratchet means with said sprocket.

5. The improvement of claim 1 wherein said ratchet means comprises elongated adjusting shaft means rotatably supported on said press,

a ratchet mechanism connected to one end of said shaft means,

a drive sprocket connected to the other end of said shaft means, and

flexible drive transmitting means interconnecting said drive sprocket with said drive means.

6. The improvement of claim 5 wherein said ratchet mechanism is located adjacent the bed of the press.

7. The improvement of claim 5 wherein said shaft means comprises a first shaft rotatably supported on said locking plate,

a second shaft rotatably supported on said frame of said press, and

universal joint means interconnecting said first and second shafts.

References Cited UNITED STATES PATENTS BILLY J. WILHITE, Primary Examiner U.S. Cl. X.R. 

